The Public Service Commission shall appoint an attorney who shall assist and advise the commission in all matters affecting its powers and duties and to perform such duties and services in connection with this chapter and the enforcement thereof as the commission may require. Such attorney shall be a member of the Mississippi State Bar, shall have practiced law for a minimum of five (5) years and shall possess considerable knowledge of utility regulation generally and of the case law, statutory law and the common law relating thereto. The attorney for the commission shall, upon request of the commission, aid in any investigation or hearing held under the provisions of this chapter. His salary shall be set by the commission, and his salary and expenses shall be paid in the same manner and from the same funds as the salary and expenses of the commissioners.